Process of producing white lead.



solution of basic lead acetate of preferably ED'WIN EUSTON, OF ST.LGUIS, MISSOTJ'RI.

PROCESS OF PRODUCING 'WI-IITE LEE-.1).

Specification of Letters Patent. Application filed September 10, 1913.

No Drawing. Serial No. 789,070.

To all whom it may concern:

Be it known that I, EDWIN EUsToN, a citizen of the United States,residing at the city of St. Louis, State of Missouri, have invented acertain new and useful Improvement in Processes of Producing White Lead,of which the following is a full, clear, and exact description, such aswill enable others skilled in the art to which it appertains to make anduse the same.

My invention relates to a process of producing white lead, my objectbeing to provide anew and easily practised. method whereby white lead ofthe best quality may be easily, cheaply and rapidly produced.

I have discovered that by separately preparing and subsequently mixingtogether the relatively bulky precipitate formed by carbon dioxid gasacting on basic lead acetate solution maintained alkaline, and therelatively dense precipitate obtained by carbon dioxid gas acting onbasic lead acetate solution until said solution is eventuallyapproximately neutral chemically, a pigment is obtained which has aopacity, whiteness, spreading and brushin qualities in every way equalto the best known commercial grades of white lead.

One simple and practical way of practising my improved process consistsin preparing, in any of the known ways, a

tion by settling or other known means in preparation for the market; orthe two products n ay be separately settled and the two precipitates sofreed from the solutions may then be mixed either before or after dryingor before or after mixing with linseed oil in preparation for themarket. The strength of solution, the strength of carbon dioxid gas, thepressure of carbon dioxid gas, the temperature and the form of apparatus may be varied and are not essential to the basic idea of myinvention which consists, first, in the precipitation of a pigment bycarbon dioxid gas from basic lead acetate solution maintained alkaline,second, in the precipitation of a pigment by carbon dioxid gas from asolution of basic lead acetate eventually approximately neutralchemically, and third, in mixing the said two pigments together inproportions to produce a pigment containing approximately from 11.0% to14.5% carbon dioXid as desired.

I claim as my invention:

1. The process of manufacturing" white lead consisting, first, informing a precipi tate by carbon dioxid gas from basic lead acetatesolution maintained alkaline, second, in forming a precipitate by carbondioxid gas from basic lead acetate solution eventually approximatelyneutral, and third, in mixing the two products thus obtained inproportions to form a pigment containing 11.0% to 14.5% carbon dioXid.

20 degrees Baum (neutral point about 10 degrees Baum) and spraying saidsolution' through an atmosphere of either dilute 2. The process ofproducing white lead or strong carbon dioxid gas in asultablevesconsisting in the admixture of a precipitate sel by a circulatingpump until most, but formed by carbon dioxidgas from a basic not all, ofthe basic leadacetate is precipitated, the solution still remainingalkaline. A second and similar solution of basic lead acetate is thenprepared and similarly treated with carbon dioxid gas until ofapproximately neutral reaction, z'. 6., neither distinctly alkaline noracid.

The two above described steps may be practised in separate apparatus oralternately in one apparatus and the two products may be directly mixedupon discharge from said apparatus and the so-mixed precipitates removedtogether from the solulead acetate solution maintained alkaline, with aprecipitate formed by carbon diosid gas from a basic lead acetatesolution eventually approximately neutral, in proportions to form apigment containing 11.0% to 14.5% carbon dioxid.

In testimony whereof I hereunto atlix my signature in the presence oftwo witnesses, this 4th day of September, 1913.

EDWTN EUSTON. W'itnesses:

M. P. SMITH, M. A. HANDEL.

Patented lill, 183214.,

